The RNA moiety of ribonuclease P is the catalytic subunit of the enzyme

Cell. 1983 Dec;35(3 Pt 2):849-57. doi: 10.1016/0092-8674(83)90117-4.


The RNA moieties of ribonuclease P purified from both E. coli (M1 RNA) and B. subtilis (P-RNA) can cleave tRNA precursor molecules in buffers containing either 60 mM Mg2+ or 10 mM Mg2+ plus 1 mM spermidine. The RNA acts as a true catalyst under these conditions whereas the protein moieties of the enzymes alone show no catalytic activity. However, in buffers containing 5-10 mM Mg2+ (in the absence of spermidine) both kinds of subunits are required for enzymatic activity, as shown previously. In the presence of low concentrations of Mg2+, in vitro, the RNA and protein subunits from one species can complement subunits from the other species in reconstitution experiments. When the precursor to E. coli 4.5S RNA is used as a substrate, only the enzyme complexes formed with M1 RNA from E. coli and the protein moieties from either bacterial species are active.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacillus subtilis / enzymology
  • Catalysis
  • Endoribonucleases / metabolism*
  • Escherichia coli / enzymology
  • Escherichia coli Proteins*
  • Kinetics
  • Magnesium / physiology
  • RNA, Bacterial / physiology*
  • Ribonuclease P
  • Species Specificity
  • Structure-Activity Relationship


  • Escherichia coli Proteins
  • RNA, Bacterial
  • Endoribonucleases
  • Ribonuclease P
  • ribonuclease P, E coli
  • Magnesium